inode.c 38 KB
Newer Older
Linus Torvalds's avatar
Linus Torvalds committed
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22
/*
 * linux/fs/inode.c
 *
 * (C) 1997 Linus Torvalds
 */

#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/dcache.h>
#include <linux/init.h>
#include <linux/quotaops.h>
#include <linux/slab.h>
#include <linux/writeback.h>
#include <linux/module.h>
#include <linux/backing-dev.h>
#include <linux/wait.h>
#include <linux/hash.h>
#include <linux/swap.h>
#include <linux/security.h>
#include <linux/pagemap.h>
#include <linux/cdev.h>
#include <linux/bootmem.h>
Robert Love's avatar
Robert Love committed
23
#include <linux/inotify.h>
24
#include <linux/mount.h>
Linus Torvalds's avatar
Linus Torvalds committed
25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57

/*
 * This is needed for the following functions:
 *  - inode_has_buffers
 *  - invalidate_inode_buffers
 *  - invalidate_bdev
 *
 * FIXME: remove all knowledge of the buffer layer from this file
 */
#include <linux/buffer_head.h>

/*
 * New inode.c implementation.
 *
 * This implementation has the basic premise of trying
 * to be extremely low-overhead and SMP-safe, yet be
 * simple enough to be "obviously correct".
 *
 * Famous last words.
 */

/* inode dynamic allocation 1999, Andrea Arcangeli <andrea@suse.de> */

/* #define INODE_PARANOIA 1 */
/* #define INODE_DEBUG 1 */

/*
 * Inode lookup is no longer as critical as it used to be:
 * most of the lookups are going to be through the dcache.
 */
#define I_HASHBITS	i_hash_shift
#define I_HASHMASK	i_hash_mask

58 59
static unsigned int i_hash_mask __read_mostly;
static unsigned int i_hash_shift __read_mostly;
Linus Torvalds's avatar
Linus Torvalds committed
60 61 62 63 64 65 66 67 68 69 70 71 72 73 74

/*
 * Each inode can be on two separate lists. One is
 * the hash list of the inode, used for lookups. The
 * other linked list is the "type" list:
 *  "in_use" - valid inode, i_count > 0, i_nlink > 0
 *  "dirty"  - as "in_use" but also dirty
 *  "unused" - valid inode, i_count = 0
 *
 * A "dirty" list is maintained for each super block,
 * allowing for low-overhead inode sync() operations.
 */

LIST_HEAD(inode_in_use);
LIST_HEAD(inode_unused);
75
static struct hlist_head *inode_hashtable __read_mostly;
Linus Torvalds's avatar
Linus Torvalds committed
76 77 78 79 80 81 82 83 84 85

/*
 * A simple spinlock to protect the list manipulations.
 *
 * NOTE! You also have to own the lock if you change
 * the i_state of an inode while it is in use..
 */
DEFINE_SPINLOCK(inode_lock);

/*
Ingo Molnar's avatar
Ingo Molnar committed
86
 * iprune_mutex provides exclusion between the kswapd or try_to_free_pages
Linus Torvalds's avatar
Linus Torvalds committed
87 88 89 90 91 92
 * icache shrinking path, and the umount path.  Without this exclusion,
 * by the time prune_icache calls iput for the inode whose pages it has
 * been invalidating, or by the time it calls clear_inode & destroy_inode
 * from its final dispose_list, the struct super_block they refer to
 * (for inode->i_sb->s_op) may already have been freed and reused.
 */
93
static DEFINE_MUTEX(iprune_mutex);
Linus Torvalds's avatar
Linus Torvalds committed
94 95 96 97 98 99

/*
 * Statistics gathering..
 */
struct inodes_stat_t inodes_stat;

100
static struct kmem_cache * inode_cachep __read_mostly;
Linus Torvalds's avatar
Linus Torvalds committed
101

Joern Engel's avatar
Joern Engel committed
102 103 104 105 106 107 108 109 110
static void wake_up_inode(struct inode *inode)
{
	/*
	 * Prevent speculative execution through spin_unlock(&inode_lock);
	 */
	smp_mb();
	wake_up_bit(&inode->i_state, __I_LOCK);
}

111 112 113 114 115 116 117 118 119
/**
 * inode_init_always - perform inode structure intialisation
 * @sb		- superblock inode belongs to.
 * @inode	- inode to initialise
 *
 * These are initializations that need to be done on every inode
 * allocation as the fields are not initialised by slab allocation.
 */
struct inode *inode_init_always(struct super_block *sb, struct inode *inode)
Linus Torvalds's avatar
Linus Torvalds committed
120
{
121
	static const struct address_space_operations empty_aops;
Linus Torvalds's avatar
Linus Torvalds committed
122
	static struct inode_operations empty_iops;
123
	static const struct file_operations empty_fops;
Linus Torvalds's avatar
Linus Torvalds committed
124

125 126 127 128 129 130 131 132 133 134 135 136 137 138
	struct address_space * const mapping = &inode->i_data;

	inode->i_sb = sb;
	inode->i_blkbits = sb->s_blocksize_bits;
	inode->i_flags = 0;
	atomic_set(&inode->i_count, 1);
	inode->i_op = &empty_iops;
	inode->i_fop = &empty_fops;
	inode->i_nlink = 1;
	atomic_set(&inode->i_writecount, 0);
	inode->i_size = 0;
	inode->i_blocks = 0;
	inode->i_bytes = 0;
	inode->i_generation = 0;
Linus Torvalds's avatar
Linus Torvalds committed
139
#ifdef CONFIG_QUOTA
140
	memset(&inode->i_dquot, 0, sizeof(inode->i_dquot));
Linus Torvalds's avatar
Linus Torvalds committed
141
#endif
142 143 144 145 146 147 148 149 150 151 152
	inode->i_pipe = NULL;
	inode->i_bdev = NULL;
	inode->i_cdev = NULL;
	inode->i_rdev = 0;
	inode->dirtied_when = 0;
	if (security_inode_alloc(inode)) {
		if (inode->i_sb->s_op->destroy_inode)
			inode->i_sb->s_op->destroy_inode(inode);
		else
			kmem_cache_free(inode_cachep, (inode));
		return NULL;
Linus Torvalds's avatar
Linus Torvalds committed
153
	}
154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187

	spin_lock_init(&inode->i_lock);
	lockdep_set_class(&inode->i_lock, &sb->s_type->i_lock_key);

	mutex_init(&inode->i_mutex);
	lockdep_set_class(&inode->i_mutex, &sb->s_type->i_mutex_key);

	init_rwsem(&inode->i_alloc_sem);
	lockdep_set_class(&inode->i_alloc_sem, &sb->s_type->i_alloc_sem_key);

	mapping->a_ops = &empty_aops;
	mapping->host = inode;
	mapping->flags = 0;
	mapping_set_gfp_mask(mapping, GFP_HIGHUSER_PAGECACHE);
	mapping->assoc_mapping = NULL;
	mapping->backing_dev_info = &default_backing_dev_info;
	mapping->writeback_index = 0;

	/*
	 * If the block_device provides a backing_dev_info for client
	 * inodes then use that.  Otherwise the inode share the bdev's
	 * backing_dev_info.
	 */
	if (sb->s_bdev) {
		struct backing_dev_info *bdi;

		bdi = sb->s_bdev->bd_inode_backing_dev_info;
		if (!bdi)
			bdi = sb->s_bdev->bd_inode->i_mapping->backing_dev_info;
		mapping->backing_dev_info = bdi;
	}
	inode->i_private = NULL;
	inode->i_mapping = mapping;

Linus Torvalds's avatar
Linus Torvalds committed
188 189
	return inode;
}
190 191 192 193 194 195 196 197 198 199 200 201 202 203 204
EXPORT_SYMBOL(inode_init_always);

static struct inode *alloc_inode(struct super_block *sb)
{
	struct inode *inode;

	if (sb->s_op->alloc_inode)
		inode = sb->s_op->alloc_inode(sb);
	else
		inode = kmem_cache_alloc(inode_cachep, GFP_KERNEL);

	if (inode)
		return inode_init_always(sb, inode);
	return NULL;
}
Linus Torvalds's avatar
Linus Torvalds committed
205 206 207

void destroy_inode(struct inode *inode) 
{
208
	BUG_ON(inode_has_buffers(inode));
Linus Torvalds's avatar
Linus Torvalds committed
209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228
	security_inode_free(inode);
	if (inode->i_sb->s_op->destroy_inode)
		inode->i_sb->s_op->destroy_inode(inode);
	else
		kmem_cache_free(inode_cachep, (inode));
}


/*
 * These are initializations that only need to be done
 * once, because the fields are idempotent across use
 * of the inode, so let the slab aware of that.
 */
void inode_init_once(struct inode *inode)
{
	memset(inode, 0, sizeof(*inode));
	INIT_HLIST_NODE(&inode->i_hash);
	INIT_LIST_HEAD(&inode->i_dentry);
	INIT_LIST_HEAD(&inode->i_devices);
	INIT_RADIX_TREE(&inode->i_data.page_tree, GFP_ATOMIC);
Nick Piggin's avatar
Nick Piggin committed
229
	spin_lock_init(&inode->i_data.tree_lock);
Linus Torvalds's avatar
Linus Torvalds committed
230 231 232 233 234 235
	spin_lock_init(&inode->i_data.i_mmap_lock);
	INIT_LIST_HEAD(&inode->i_data.private_list);
	spin_lock_init(&inode->i_data.private_lock);
	INIT_RAW_PRIO_TREE_ROOT(&inode->i_data.i_mmap);
	INIT_LIST_HEAD(&inode->i_data.i_mmap_nonlinear);
	i_size_ordered_init(inode);
Robert Love's avatar
Robert Love committed
236 237
#ifdef CONFIG_INOTIFY
	INIT_LIST_HEAD(&inode->inotify_watches);
Ingo Molnar's avatar
Ingo Molnar committed
238
	mutex_init(&inode->inotify_mutex);
Robert Love's avatar
Robert Love committed
239
#endif
Linus Torvalds's avatar
Linus Torvalds committed
240 241 242 243
}

EXPORT_SYMBOL(inode_init_once);

244
static void init_once(void *foo)
Linus Torvalds's avatar
Linus Torvalds committed
245 246 247
{
	struct inode * inode = (struct inode *) foo;

248
	inode_init_once(inode);
Linus Torvalds's avatar
Linus Torvalds committed
249 250 251 252 253 254 255 256 257 258 259 260
}

/*
 * inode_lock must be held
 */
void __iget(struct inode * inode)
{
	if (atomic_read(&inode->i_count)) {
		atomic_inc(&inode->i_count);
		return;
	}
	atomic_inc(&inode->i_count);
Joern Engel's avatar
Joern Engel committed
261
	if (!(inode->i_state & (I_DIRTY|I_SYNC)))
Linus Torvalds's avatar
Linus Torvalds committed
262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278
		list_move(&inode->i_list, &inode_in_use);
	inodes_stat.nr_unused--;
}

/**
 * clear_inode - clear an inode
 * @inode: inode to clear
 *
 * This is called by the filesystem to tell us
 * that the inode is no longer useful. We just
 * terminate it with extreme prejudice.
 */
void clear_inode(struct inode *inode)
{
	might_sleep();
	invalidate_inode_buffers(inode);
       
279 280 281
	BUG_ON(inode->i_data.nrpages);
	BUG_ON(!(inode->i_state & I_FREEING));
	BUG_ON(inode->i_state & I_CLEAR);
Joern Engel's avatar
Joern Engel committed
282
	inode_sync_wait(inode);
Linus Torvalds's avatar
Linus Torvalds committed
283
	DQUOT_DROP(inode);
284
	if (inode->i_sb->s_op->clear_inode)
Linus Torvalds's avatar
Linus Torvalds committed
285
		inode->i_sb->s_op->clear_inode(inode);
286
	if (S_ISBLK(inode->i_mode) && inode->i_bdev)
Linus Torvalds's avatar
Linus Torvalds committed
287
		bd_forget(inode);
288
	if (S_ISCHR(inode->i_mode) && inode->i_cdev)
Linus Torvalds's avatar
Linus Torvalds committed
289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308
		cd_forget(inode);
	inode->i_state = I_CLEAR;
}

EXPORT_SYMBOL(clear_inode);

/*
 * dispose_list - dispose of the contents of a local list
 * @head: the head of the list to free
 *
 * Dispose-list gets a local list with local inodes in it, so it doesn't
 * need to worry about list corruption and SMP locks.
 */
static void dispose_list(struct list_head *head)
{
	int nr_disposed = 0;

	while (!list_empty(head)) {
		struct inode *inode;

309
		inode = list_first_entry(head, struct inode, i_list);
Linus Torvalds's avatar
Linus Torvalds committed
310 311 312 313 314
		list_del(&inode->i_list);

		if (inode->i_data.nrpages)
			truncate_inode_pages(&inode->i_data, 0);
		clear_inode(inode);
315 316 317 318 319 320 321

		spin_lock(&inode_lock);
		hlist_del_init(&inode->i_hash);
		list_del_init(&inode->i_sb_list);
		spin_unlock(&inode_lock);

		wake_up_inode(inode);
Linus Torvalds's avatar
Linus Torvalds committed
322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345
		destroy_inode(inode);
		nr_disposed++;
	}
	spin_lock(&inode_lock);
	inodes_stat.nr_inodes -= nr_disposed;
	spin_unlock(&inode_lock);
}

/*
 * Invalidate all inodes for a device.
 */
static int invalidate_list(struct list_head *head, struct list_head *dispose)
{
	struct list_head *next;
	int busy = 0, count = 0;

	next = head->next;
	for (;;) {
		struct list_head * tmp = next;
		struct inode * inode;

		/*
		 * We can reschedule here without worrying about the list's
		 * consistency because the per-sb list of inodes must not
Ingo Molnar's avatar
Ingo Molnar committed
346
		 * change during umount anymore, and because iprune_mutex keeps
Linus Torvalds's avatar
Linus Torvalds committed
347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381
		 * shrink_icache_memory() away.
		 */
		cond_resched_lock(&inode_lock);

		next = next->next;
		if (tmp == head)
			break;
		inode = list_entry(tmp, struct inode, i_sb_list);
		invalidate_inode_buffers(inode);
		if (!atomic_read(&inode->i_count)) {
			list_move(&inode->i_list, dispose);
			inode->i_state |= I_FREEING;
			count++;
			continue;
		}
		busy = 1;
	}
	/* only unused inodes may be cached with i_count zero */
	inodes_stat.nr_unused -= count;
	return busy;
}

/**
 *	invalidate_inodes	- discard the inodes on a device
 *	@sb: superblock
 *
 *	Discard all of the inodes for a given superblock. If the discard
 *	fails because there are busy inodes then a non zero value is returned.
 *	If the discard is successful all the inodes have been discarded.
 */
int invalidate_inodes(struct super_block * sb)
{
	int busy;
	LIST_HEAD(throw_away);

Ingo Molnar's avatar
Ingo Molnar committed
382
	mutex_lock(&iprune_mutex);
Linus Torvalds's avatar
Linus Torvalds committed
383
	spin_lock(&inode_lock);
Robert Love's avatar
Robert Love committed
384
	inotify_unmount_inodes(&sb->s_inodes);
Linus Torvalds's avatar
Linus Torvalds committed
385 386 387 388
	busy = invalidate_list(&sb->s_inodes, &throw_away);
	spin_unlock(&inode_lock);

	dispose_list(&throw_away);
Ingo Molnar's avatar
Ingo Molnar committed
389
	mutex_unlock(&iprune_mutex);
Linus Torvalds's avatar
Linus Torvalds committed
390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428

	return busy;
}

EXPORT_SYMBOL(invalidate_inodes);

static int can_unuse(struct inode *inode)
{
	if (inode->i_state)
		return 0;
	if (inode_has_buffers(inode))
		return 0;
	if (atomic_read(&inode->i_count))
		return 0;
	if (inode->i_data.nrpages)
		return 0;
	return 1;
}

/*
 * Scan `goal' inodes on the unused list for freeable ones. They are moved to
 * a temporary list and then are freed outside inode_lock by dispose_list().
 *
 * Any inodes which are pinned purely because of attached pagecache have their
 * pagecache removed.  We expect the final iput() on that inode to add it to
 * the front of the inode_unused list.  So look for it there and if the
 * inode is still freeable, proceed.  The right inode is found 99.9% of the
 * time in testing on a 4-way.
 *
 * If the inode has metadata buffers attached to mapping->private_list then
 * try to remove them.
 */
static void prune_icache(int nr_to_scan)
{
	LIST_HEAD(freeable);
	int nr_pruned = 0;
	int nr_scanned;
	unsigned long reap = 0;

Ingo Molnar's avatar
Ingo Molnar committed
429
	mutex_lock(&iprune_mutex);
Linus Torvalds's avatar
Linus Torvalds committed
430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446
	spin_lock(&inode_lock);
	for (nr_scanned = 0; nr_scanned < nr_to_scan; nr_scanned++) {
		struct inode *inode;

		if (list_empty(&inode_unused))
			break;

		inode = list_entry(inode_unused.prev, struct inode, i_list);

		if (inode->i_state || atomic_read(&inode->i_count)) {
			list_move(&inode->i_list, &inode_unused);
			continue;
		}
		if (inode_has_buffers(inode) || inode->i_data.nrpages) {
			__iget(inode);
			spin_unlock(&inode_lock);
			if (remove_inode_buffers(inode))
447 448
				reap += invalidate_mapping_pages(&inode->i_data,
								0, -1);
Linus Torvalds's avatar
Linus Torvalds committed
449 450 451 452 453 454 455 456 457 458 459 460 461 462
			iput(inode);
			spin_lock(&inode_lock);

			if (inode != list_entry(inode_unused.next,
						struct inode, i_list))
				continue;	/* wrong inode or list_empty */
			if (!can_unuse(inode))
				continue;
		}
		list_move(&inode->i_list, &freeable);
		inode->i_state |= I_FREEING;
		nr_pruned++;
	}
	inodes_stat.nr_unused -= nr_pruned;
463 464 465 466
	if (current_is_kswapd())
		__count_vm_events(KSWAPD_INODESTEAL, reap);
	else
		__count_vm_events(PGINODESTEAL, reap);
Linus Torvalds's avatar
Linus Torvalds committed
467 468 469
	spin_unlock(&inode_lock);

	dispose_list(&freeable);
Ingo Molnar's avatar
Ingo Molnar committed
470
	mutex_unlock(&iprune_mutex);
Linus Torvalds's avatar
Linus Torvalds committed
471 472 473 474 475 476 477 478 479 480 481
}

/*
 * shrink_icache_memory() will attempt to reclaim some unused inodes.  Here,
 * "unused" means that no dentries are referring to the inodes: the files are
 * not open and the dcache references to those inodes have already been
 * reclaimed.
 *
 * This function is passed the number of inodes to scan, and it returns the
 * total number of remaining possibly-reclaimable inodes.
 */
Al Viro's avatar
Al Viro committed
482
static int shrink_icache_memory(int nr, gfp_t gfp_mask)
Linus Torvalds's avatar
Linus Torvalds committed
483 484 485 486 487 488 489 490 491 492 493 494 495 496
{
	if (nr) {
		/*
		 * Nasty deadlock avoidance.  We may hold various FS locks,
		 * and we don't want to recurse into the FS that called us
		 * in clear_inode() and friends..
	 	 */
		if (!(gfp_mask & __GFP_FS))
			return -1;
		prune_icache(nr);
	}
	return (inodes_stat.nr_unused / 100) * sysctl_vfs_cache_pressure;
}

497 498 499 500 501
static struct shrinker icache_shrinker = {
	.shrink = shrink_icache_memory,
	.seeks = DEFAULT_SEEKS,
};

Linus Torvalds's avatar
Linus Torvalds committed
502 503 504 505 506 507 508 509 510 511 512 513 514
static void __wait_on_freeing_inode(struct inode *inode);
/*
 * Called with the inode lock held.
 * NOTE: we are not increasing the inode-refcount, you must call __iget()
 * by hand after calling find_inode now! This simplifies iunique and won't
 * add any additional branch in the common code.
 */
static struct inode * find_inode(struct super_block * sb, struct hlist_head *head, int (*test)(struct inode *, void *), void *data)
{
	struct hlist_node *node;
	struct inode * inode = NULL;

repeat:
515
	hlist_for_each_entry(inode, node, head, i_hash) {
Linus Torvalds's avatar
Linus Torvalds committed
516 517 518 519
		if (inode->i_sb != sb)
			continue;
		if (!test(inode, data))
			continue;
520
		if (inode->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE)) {
Linus Torvalds's avatar
Linus Torvalds committed
521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538
			__wait_on_freeing_inode(inode);
			goto repeat;
		}
		break;
	}
	return node ? inode : NULL;
}

/*
 * find_inode_fast is the fast path version of find_inode, see the comment at
 * iget_locked for details.
 */
static struct inode * find_inode_fast(struct super_block * sb, struct hlist_head *head, unsigned long ino)
{
	struct hlist_node *node;
	struct inode * inode = NULL;

repeat:
539
	hlist_for_each_entry(inode, node, head, i_hash) {
Linus Torvalds's avatar
Linus Torvalds committed
540 541 542 543
		if (inode->i_ino != ino)
			continue;
		if (inode->i_sb != sb)
			continue;
544
		if (inode->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE)) {
Linus Torvalds's avatar
Linus Torvalds committed
545 546 547 548 549 550 551 552 553 554 555 556
			__wait_on_freeing_inode(inode);
			goto repeat;
		}
		break;
	}
	return node ? inode : NULL;
}

/**
 *	new_inode 	- obtain an inode
 *	@sb: superblock
 *
557 558 559 560 561 562 563
 *	Allocates a new inode for given superblock. The default gfp_mask
 *	for allocations related to inode->i_mapping is GFP_HIGHUSER_PAGECACHE.
 *	If HIGHMEM pages are unsuitable or it is known that pages allocated
 *	for the page cache are not reclaimable or migratable,
 *	mapping_set_gfp_mask() must be called with suitable flags on the
 *	newly created inode's mapping
 *
Linus Torvalds's avatar
Linus Torvalds committed
564 565 566
 */
struct inode *new_inode(struct super_block *sb)
{
567 568 569 570 571 572
	/*
	 * On a 32bit, non LFS stat() call, glibc will generate an EOVERFLOW
	 * error if st_ino won't fit in target struct field. Use 32bit counter
	 * here to attempt to avoid that.
	 */
	static unsigned int last_ino;
Linus Torvalds's avatar
Linus Torvalds committed
573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593
	struct inode * inode;

	spin_lock_prefetch(&inode_lock);
	
	inode = alloc_inode(sb);
	if (inode) {
		spin_lock(&inode_lock);
		inodes_stat.nr_inodes++;
		list_add(&inode->i_list, &inode_in_use);
		list_add(&inode->i_sb_list, &sb->s_inodes);
		inode->i_ino = ++last_ino;
		inode->i_state = 0;
		spin_unlock(&inode_lock);
	}
	return inode;
}

EXPORT_SYMBOL(new_inode);

void unlock_new_inode(struct inode *inode)
{
594
#ifdef CONFIG_DEBUG_LOCK_ALLOC
595 596 597 598 599 600 601 602
	if (inode->i_mode & S_IFDIR) {
		struct file_system_type *type = inode->i_sb->s_type;

		/*
		 * ensure nobody is actually holding i_mutex
		 */
		mutex_destroy(&inode->i_mutex);
		mutex_init(&inode->i_mutex);
603
		lockdep_set_class(&inode->i_mutex, &type->i_mutex_dir_key);
604
	}
605
#endif
Linus Torvalds's avatar
Linus Torvalds committed
606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716
	/*
	 * This is special!  We do not need the spinlock
	 * when clearing I_LOCK, because we're guaranteed
	 * that nobody else tries to do anything about the
	 * state of the inode when it is locked, as we
	 * just created it (so there can be no old holders
	 * that haven't tested I_LOCK).
	 */
	inode->i_state &= ~(I_LOCK|I_NEW);
	wake_up_inode(inode);
}

EXPORT_SYMBOL(unlock_new_inode);

/*
 * This is called without the inode lock held.. Be careful.
 *
 * We no longer cache the sb_flags in i_flags - see fs.h
 *	-- rmk@arm.uk.linux.org
 */
static struct inode * get_new_inode(struct super_block *sb, struct hlist_head *head, int (*test)(struct inode *, void *), int (*set)(struct inode *, void *), void *data)
{
	struct inode * inode;

	inode = alloc_inode(sb);
	if (inode) {
		struct inode * old;

		spin_lock(&inode_lock);
		/* We released the lock, so.. */
		old = find_inode(sb, head, test, data);
		if (!old) {
			if (set(inode, data))
				goto set_failed;

			inodes_stat.nr_inodes++;
			list_add(&inode->i_list, &inode_in_use);
			list_add(&inode->i_sb_list, &sb->s_inodes);
			hlist_add_head(&inode->i_hash, head);
			inode->i_state = I_LOCK|I_NEW;
			spin_unlock(&inode_lock);

			/* Return the locked inode with I_NEW set, the
			 * caller is responsible for filling in the contents
			 */
			return inode;
		}

		/*
		 * Uhhuh, somebody else created the same inode under
		 * us. Use the old inode instead of the one we just
		 * allocated.
		 */
		__iget(old);
		spin_unlock(&inode_lock);
		destroy_inode(inode);
		inode = old;
		wait_on_inode(inode);
	}
	return inode;

set_failed:
	spin_unlock(&inode_lock);
	destroy_inode(inode);
	return NULL;
}

/*
 * get_new_inode_fast is the fast path version of get_new_inode, see the
 * comment at iget_locked for details.
 */
static struct inode * get_new_inode_fast(struct super_block *sb, struct hlist_head *head, unsigned long ino)
{
	struct inode * inode;

	inode = alloc_inode(sb);
	if (inode) {
		struct inode * old;

		spin_lock(&inode_lock);
		/* We released the lock, so.. */
		old = find_inode_fast(sb, head, ino);
		if (!old) {
			inode->i_ino = ino;
			inodes_stat.nr_inodes++;
			list_add(&inode->i_list, &inode_in_use);
			list_add(&inode->i_sb_list, &sb->s_inodes);
			hlist_add_head(&inode->i_hash, head);
			inode->i_state = I_LOCK|I_NEW;
			spin_unlock(&inode_lock);

			/* Return the locked inode with I_NEW set, the
			 * caller is responsible for filling in the contents
			 */
			return inode;
		}

		/*
		 * Uhhuh, somebody else created the same inode under
		 * us. Use the old inode instead of the one we just
		 * allocated.
		 */
		__iget(old);
		spin_unlock(&inode_lock);
		destroy_inode(inode);
		inode = old;
		wait_on_inode(inode);
	}
	return inode;
}

Andreas Mohr's avatar
Andreas Mohr committed
717
static unsigned long hash(struct super_block *sb, unsigned long hashval)
Linus Torvalds's avatar
Linus Torvalds committed
718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742
{
	unsigned long tmp;

	tmp = (hashval * (unsigned long)sb) ^ (GOLDEN_RATIO_PRIME + hashval) /
			L1_CACHE_BYTES;
	tmp = tmp ^ ((tmp ^ GOLDEN_RATIO_PRIME) >> I_HASHBITS);
	return tmp & I_HASHMASK;
}

/**
 *	iunique - get a unique inode number
 *	@sb: superblock
 *	@max_reserved: highest reserved inode number
 *
 *	Obtain an inode number that is unique on the system for a given
 *	superblock. This is used by file systems that have no natural
 *	permanent inode numbering system. An inode number is returned that
 *	is higher than the reserved limit but unique.
 *
 *	BUGS:
 *	With a large number of inodes live on the file system this function
 *	currently becomes quite slow.
 */
ino_t iunique(struct super_block *sb, ino_t max_reserved)
{
743 744 745 746 747 748
	/*
	 * On a 32bit, non LFS stat() call, glibc will generate an EOVERFLOW
	 * error if st_ino won't fit in target struct field. Use 32bit counter
	 * here to attempt to avoid that.
	 */
	static unsigned int counter;
Linus Torvalds's avatar
Linus Torvalds committed
749
	struct inode *inode;
750
	struct hlist_head *head;
Linus Torvalds's avatar
Linus Torvalds committed
751
	ino_t res;
752

Linus Torvalds's avatar
Linus Torvalds committed
753
	spin_lock(&inode_lock);
754 755 756
	do {
		if (counter <= max_reserved)
			counter = max_reserved + 1;
Linus Torvalds's avatar
Linus Torvalds committed
757
		res = counter++;
758
		head = inode_hashtable + hash(sb, res);
Linus Torvalds's avatar
Linus Torvalds committed
759
		inode = find_inode_fast(sb, head, res);
760 761
	} while (inode != NULL);
	spin_unlock(&inode_lock);
Linus Torvalds's avatar
Linus Torvalds committed
762

763 764
	return res;
}
Linus Torvalds's avatar
Linus Torvalds committed
765 766 767 768 769
EXPORT_SYMBOL(iunique);

struct inode *igrab(struct inode *inode)
{
	spin_lock(&inode_lock);
770
	if (!(inode->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE)))
Linus Torvalds's avatar
Linus Torvalds committed
771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790
		__iget(inode);
	else
		/*
		 * Handle the case where s_op->clear_inode is not been
		 * called yet, and somebody is calling igrab
		 * while the inode is getting freed.
		 */
		inode = NULL;
	spin_unlock(&inode_lock);
	return inode;
}

EXPORT_SYMBOL(igrab);

/**
 * ifind - internal function, you want ilookup5() or iget5().
 * @sb:		super block of file system to search
 * @head:       the head of the list to search
 * @test:	callback used for comparisons between inodes
 * @data:	opaque data pointer to pass to @test
791
 * @wait:	if true wait for the inode to be unlocked, if false do not
Linus Torvalds's avatar
Linus Torvalds committed
792 793 794 795 796 797 798 799 800 801 802 803
 *
 * ifind() searches for the inode specified by @data in the inode
 * cache. This is a generalized version of ifind_fast() for file systems where
 * the inode number is not sufficient for unique identification of an inode.
 *
 * If the inode is in the cache, the inode is returned with an incremented
 * reference count.
 *
 * Otherwise NULL is returned.
 *
 * Note, @test is called with the inode_lock held, so can't sleep.
 */
804
static struct inode *ifind(struct super_block *sb,
Linus Torvalds's avatar
Linus Torvalds committed
805
		struct hlist_head *head, int (*test)(struct inode *, void *),
806
		void *data, const int wait)
Linus Torvalds's avatar
Linus Torvalds committed
807 808 809 810 811 812 813 814
{
	struct inode *inode;

	spin_lock(&inode_lock);
	inode = find_inode(sb, head, test, data);
	if (inode) {
		__iget(inode);
		spin_unlock(&inode_lock);
815 816
		if (likely(wait))
			wait_on_inode(inode);
Linus Torvalds's avatar
Linus Torvalds committed
817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837
		return inode;
	}
	spin_unlock(&inode_lock);
	return NULL;
}

/**
 * ifind_fast - internal function, you want ilookup() or iget().
 * @sb:		super block of file system to search
 * @head:       head of the list to search
 * @ino:	inode number to search for
 *
 * ifind_fast() searches for the inode @ino in the inode cache. This is for
 * file systems where the inode number is sufficient for unique identification
 * of an inode.
 *
 * If the inode is in the cache, the inode is returned with an incremented
 * reference count.
 *
 * Otherwise NULL is returned.
 */
838
static struct inode *ifind_fast(struct super_block *sb,
Linus Torvalds's avatar
Linus Torvalds committed
839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855
		struct hlist_head *head, unsigned long ino)
{
	struct inode *inode;

	spin_lock(&inode_lock);
	inode = find_inode_fast(sb, head, ino);
	if (inode) {
		__iget(inode);
		spin_unlock(&inode_lock);
		wait_on_inode(inode);
		return inode;
	}
	spin_unlock(&inode_lock);
	return NULL;
}

/**
856
 * ilookup5_nowait - search for an inode in the inode cache
Linus Torvalds's avatar
Linus Torvalds committed
857 858 859 860 861 862 863 864 865 866 867
 * @sb:		super block of file system to search
 * @hashval:	hash value (usually inode number) to search for
 * @test:	callback used for comparisons between inodes
 * @data:	opaque data pointer to pass to @test
 *
 * ilookup5() uses ifind() to search for the inode specified by @hashval and
 * @data in the inode cache. This is a generalized version of ilookup() for
 * file systems where the inode number is not sufficient for unique
 * identification of an inode.
 *
 * If the inode is in the cache, the inode is returned with an incremented
868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899
 * reference count.  Note, the inode lock is not waited upon so you have to be
 * very careful what you do with the returned inode.  You probably should be
 * using ilookup5() instead.
 *
 * Otherwise NULL is returned.
 *
 * Note, @test is called with the inode_lock held, so can't sleep.
 */
struct inode *ilookup5_nowait(struct super_block *sb, unsigned long hashval,
		int (*test)(struct inode *, void *), void *data)
{
	struct hlist_head *head = inode_hashtable + hash(sb, hashval);

	return ifind(sb, head, test, data, 0);
}

EXPORT_SYMBOL(ilookup5_nowait);

/**
 * ilookup5 - search for an inode in the inode cache
 * @sb:		super block of file system to search
 * @hashval:	hash value (usually inode number) to search for
 * @test:	callback used for comparisons between inodes
 * @data:	opaque data pointer to pass to @test
 *
 * ilookup5() uses ifind() to search for the inode specified by @hashval and
 * @data in the inode cache. This is a generalized version of ilookup() for
 * file systems where the inode number is not sufficient for unique
 * identification of an inode.
 *
 * If the inode is in the cache, the inode lock is waited upon and the inode is
 * returned with an incremented reference count.
Linus Torvalds's avatar
Linus Torvalds committed
900 901 902 903 904 905 906 907 908 909
 *
 * Otherwise NULL is returned.
 *
 * Note, @test is called with the inode_lock held, so can't sleep.
 */
struct inode *ilookup5(struct super_block *sb, unsigned long hashval,
		int (*test)(struct inode *, void *), void *data)
{
	struct hlist_head *head = inode_hashtable + hash(sb, hashval);

910
	return ifind(sb, head, test, data, 1);
Linus Torvalds's avatar
Linus Torvalds committed
911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964
}

EXPORT_SYMBOL(ilookup5);

/**
 * ilookup - search for an inode in the inode cache
 * @sb:		super block of file system to search
 * @ino:	inode number to search for
 *
 * ilookup() uses ifind_fast() to search for the inode @ino in the inode cache.
 * This is for file systems where the inode number is sufficient for unique
 * identification of an inode.
 *
 * If the inode is in the cache, the inode is returned with an incremented
 * reference count.
 *
 * Otherwise NULL is returned.
 */
struct inode *ilookup(struct super_block *sb, unsigned long ino)
{
	struct hlist_head *head = inode_hashtable + hash(sb, ino);

	return ifind_fast(sb, head, ino);
}

EXPORT_SYMBOL(ilookup);

/**
 * iget5_locked - obtain an inode from a mounted file system
 * @sb:		super block of file system
 * @hashval:	hash value (usually inode number) to get
 * @test:	callback used for comparisons between inodes
 * @set:	callback used to initialize a new struct inode
 * @data:	opaque data pointer to pass to @test and @set
 *
 * iget5_locked() uses ifind() to search for the inode specified by @hashval
 * and @data in the inode cache and if present it is returned with an increased
 * reference count. This is a generalized version of iget_locked() for file
 * systems where the inode number is not sufficient for unique identification
 * of an inode.
 *
 * If the inode is not in cache, get_new_inode() is called to allocate a new
 * inode and this is returned locked, hashed, and with the I_NEW flag set. The
 * file system gets to fill it in before unlocking it via unlock_new_inode().
 *
 * Note both @test and @set are called with the inode_lock held, so can't sleep.
 */
struct inode *iget5_locked(struct super_block *sb, unsigned long hashval,
		int (*test)(struct inode *, void *),
		int (*set)(struct inode *, void *), void *data)
{
	struct hlist_head *head = inode_hashtable + hash(sb, hashval);
	struct inode *inode;

965
	inode = ifind(sb, head, test, data, 1);
Linus Torvalds's avatar
Linus Torvalds committed
966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055
	if (inode)
		return inode;
	/*
	 * get_new_inode() will do the right thing, re-trying the search
	 * in case it had to block at any point.
	 */
	return get_new_inode(sb, head, test, set, data);
}

EXPORT_SYMBOL(iget5_locked);

/**
 * iget_locked - obtain an inode from a mounted file system
 * @sb:		super block of file system
 * @ino:	inode number to get
 *
 * iget_locked() uses ifind_fast() to search for the inode specified by @ino in
 * the inode cache and if present it is returned with an increased reference
 * count. This is for file systems where the inode number is sufficient for
 * unique identification of an inode.
 *
 * If the inode is not in cache, get_new_inode_fast() is called to allocate a
 * new inode and this is returned locked, hashed, and with the I_NEW flag set.
 * The file system gets to fill it in before unlocking it via
 * unlock_new_inode().
 */
struct inode *iget_locked(struct super_block *sb, unsigned long ino)
{
	struct hlist_head *head = inode_hashtable + hash(sb, ino);
	struct inode *inode;

	inode = ifind_fast(sb, head, ino);
	if (inode)
		return inode;
	/*
	 * get_new_inode_fast() will do the right thing, re-trying the search
	 * in case it had to block at any point.
	 */
	return get_new_inode_fast(sb, head, ino);
}

EXPORT_SYMBOL(iget_locked);

/**
 *	__insert_inode_hash - hash an inode
 *	@inode: unhashed inode
 *	@hashval: unsigned long value used to locate this object in the
 *		inode_hashtable.
 *
 *	Add an inode to the inode hash for this superblock.
 */
void __insert_inode_hash(struct inode *inode, unsigned long hashval)
{
	struct hlist_head *head = inode_hashtable + hash(inode->i_sb, hashval);
	spin_lock(&inode_lock);
	hlist_add_head(&inode->i_hash, head);
	spin_unlock(&inode_lock);
}

EXPORT_SYMBOL(__insert_inode_hash);

/**
 *	remove_inode_hash - remove an inode from the hash
 *	@inode: inode to unhash
 *
 *	Remove an inode from the superblock.
 */
void remove_inode_hash(struct inode *inode)
{
	spin_lock(&inode_lock);
	hlist_del_init(&inode->i_hash);
	spin_unlock(&inode_lock);
}

EXPORT_SYMBOL(remove_inode_hash);

/*
 * Tell the filesystem that this inode is no longer of any interest and should
 * be completely destroyed.
 *
 * We leave the inode in the inode hash table until *after* the filesystem's
 * ->delete_inode completes.  This ensures that an iget (such as nfsd might
 * instigate) will always find up-to-date information either in the hash or on
 * disk.
 *
 * I_FREEING is set so that no-one will take a new reference to the inode while
 * it is being deleted.
 */
void generic_delete_inode(struct inode *inode)
{
1056
	const struct super_operations *op = inode->i_sb->s_op;
Linus Torvalds's avatar
Linus Torvalds committed
1057 1058 1059

	list_del_init(&inode->i_list);
	list_del_init(&inode->i_sb_list);
Andreas Mohr's avatar
Andreas Mohr committed
1060
	inode->i_state |= I_FREEING;
Linus Torvalds's avatar
Linus Torvalds committed
1061 1062 1063 1064 1065 1066 1067 1068 1069
	inodes_stat.nr_inodes--;
	spin_unlock(&inode_lock);

	security_inode_delete(inode);

	if (op->delete_inode) {
		void (*delete)(struct inode *) = op->delete_inode;
		if (!is_bad_inode(inode))
			DQUOT_INIT(inode);
1070 1071 1072 1073
		/* Filesystems implementing their own
		 * s_op->delete_inode are required to call
		 * truncate_inode_pages and clear_inode()
		 * internally */
Linus Torvalds's avatar
Linus Torvalds committed
1074
		delete(inode);
1075 1076
	} else {
		truncate_inode_pages(&inode->i_data, 0);
Linus Torvalds's avatar
Linus Torvalds committed
1077
		clear_inode(inode);
1078
	}
Linus Torvalds's avatar
Linus Torvalds committed
1079 1080 1081 1082
	spin_lock(&inode_lock);
	hlist_del_init(&inode->i_hash);
	spin_unlock(&inode_lock);
	wake_up_inode(inode);
1083
	BUG_ON(inode->i_state != I_CLEAR);
Linus Torvalds's avatar
Linus Torvalds committed
1084 1085 1086 1087 1088 1089 1090 1091 1092 1093
	destroy_inode(inode);
}

EXPORT_SYMBOL(generic_delete_inode);

static void generic_forget_inode(struct inode *inode)
{
	struct super_block *sb = inode->i_sb;

	if (!hlist_unhashed(&inode->i_hash)) {
Joern Engel's avatar
Joern Engel committed
1094
		if (!(inode->i_state & (I_DIRTY|I_SYNC)))
Linus Torvalds's avatar
Linus Torvalds committed
1095 1096
			list_move(&inode->i_list, &inode_unused);
		inodes_stat.nr_unused++;
1097
		if (sb->s_flags & MS_ACTIVE) {
1098
			spin_unlock(&inode_lock);
Linus Torvalds's avatar
Linus Torvalds committed
1099
			return;
1100 1101 1102
		}
		inode->i_state |= I_WILL_FREE;
		spin_unlock(&inode_lock);
Linus Torvalds's avatar
Linus Torvalds committed
1103 1104
		write_inode_now(inode, 1);
		spin_lock(&inode_lock);
1105
		inode->i_state &= ~I_WILL_FREE;
Linus Torvalds's avatar
Linus Torvalds committed
1106 1107 1108 1109 1110
		inodes_stat.nr_unused--;
		hlist_del_init(&inode->i_hash);
	}
	list_del_init(&inode->i_list);
	list_del_init(&inode->i_sb_list);
1111
	inode->i_state |= I_FREEING;
Linus Torvalds's avatar
Linus Torvalds committed
1112 1113 1114 1115 1116
	inodes_stat.nr_inodes--;
	spin_unlock(&inode_lock);
	if (inode->i_data.nrpages)
		truncate_inode_pages(&inode->i_data, 0);
	clear_inode(inode);
1117
	wake_up_inode(inode);
Linus Torvalds's avatar
Linus Torvalds committed
1118 1119 1120 1121 1122 1123 1124 1125
	destroy_inode(inode);
}

/*
 * Normal UNIX filesystem behaviour: delete the
 * inode when the usage count drops to zero, and
 * i_nlink is zero.
 */
1126
void generic_drop_inode(struct inode *inode)
Linus Torvalds's avatar
Linus Torvalds committed
1127 1128 1129 1130 1131 1132 1133
{
	if (!inode->i_nlink)
		generic_delete_inode(inode);
	else
		generic_forget_inode(inode);
}

1134 1135
EXPORT_SYMBOL_GPL(generic_drop_inode);

Linus Torvalds's avatar
Linus Torvalds committed
1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148
/*
 * Called when we're dropping the last reference
 * to an inode. 
 *
 * Call the FS "drop()" function, defaulting to
 * the legacy UNIX filesystem behaviour..
 *
 * NOTE! NOTE! NOTE! We're called with the inode lock
 * held, and the drop function is supposed to release
 * the lock!
 */
static inline void iput_final(struct inode *inode)
{
1149
	const struct super_operations *op = inode->i_sb->s_op;
Linus Torvalds's avatar
Linus Torvalds committed
1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198
	void (*drop)(struct inode *) = generic_drop_inode;

	if (op && op->drop_inode)
		drop = op->drop_inode;
	drop(inode);
}

/**
 *	iput	- put an inode 
 *	@inode: inode to put
 *
 *	Puts an inode, dropping its usage count. If the inode use count hits
 *	zero, the inode is then freed and may also be destroyed.
 *
 *	Consequently, iput() can sleep.
 */
void iput(struct inode *inode)
{
	if (inode) {
		BUG_ON(inode->i_state == I_CLEAR);

		if (atomic_dec_and_lock(&inode->i_count, &inode_lock))
			iput_final(inode);
	}
}

EXPORT_SYMBOL(iput);

/**
 *	bmap	- find a block number in a file
 *	@inode: inode of file
 *	@block: block to find
 *
 *	Returns the block number on the device holding the inode that
 *	is the disk block number for the block of the file requested.
 *	That is, asked for block 4 of inode 1 the function will return the
 *	disk block relative to the disk start that holds that block of the 
 *	file.
 */
sector_t bmap(struct inode * inode, sector_t block)
{
	sector_t res = 0;
	if (inode->i_mapping->a_ops->bmap)
		res = inode->i_mapping->a_ops->bmap(inode->i_mapping, block);
	return res;
}
EXPORT_SYMBOL(bmap);

/**
1199 1200
 *	touch_atime	-	update the access time
 *	@mnt: mount the inode is accessed on
1201
 *	@dentry: dentry accessed
Linus Torvalds's avatar
Linus Torvalds committed
1202 1203 1204 1205 1206
 *
 *	Update the accessed time on an inode and mark it for writeback.
 *	This function automatically handles read only file systems and media,
 *	as well as the "noatime" flag and inode specific "noatime" markers.
 */
1207
void touch_atime(struct vfsmount *mnt, struct dentry *dentry)
Linus Torvalds's avatar
Linus Torvalds committed
1208
{
1209
	struct inode *inode = dentry->d_inode;
Linus Torvalds's avatar
Linus Torvalds committed
1210 1211
	struct timespec now;

1212
	if (mnt_want_write(mnt))
Andrew Morton's avatar
Andrew Morton committed
1213
		return;
1214 1215
	if (inode->i_flags & S_NOATIME)
		goto out;
1216
	if (IS_NOATIME(inode))
1217
		goto out;
Andrew Morton's avatar
Andrew Morton committed
1218
	if ((inode->i_sb->s_flags & MS_NODIRATIME) && S_ISDIR(inode->i_mode))
1219
		goto out;
Valerie Henson's avatar
Valerie Henson committed
1220

1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232
	if (mnt->mnt_flags & MNT_NOATIME)
		goto out;
	if ((mnt->mnt_flags & MNT_NODIRATIME) && S_ISDIR(inode->i_mode))
		goto out;
	if (mnt->mnt_flags & MNT_RELATIME) {
		/*
		 * With relative atime, only update atime if the previous
		 * atime is earlier than either the ctime or mtime.
		 */
		if (timespec_compare(&inode->i_mtime, &inode->i_atime) < 0 &&
		    timespec_compare(&inode->i_ctime, &inode->i_atime) < 0)
			goto out;
Andrew Morton's avatar
Andrew Morton committed
1233
	}
Linus Torvalds's avatar
Linus Torvalds committed
1234 1235

	now = current_fs_time(inode->i_sb);
Valerie Henson's avatar
Valerie Henson committed
1236
	if (timespec_equal(&inode->i_atime, &now))
1237
		goto out;
Valerie Henson's avatar
Valerie Henson committed
1238 1239 1240

	inode->i_atime = now;
	mark_inode_dirty_sync(inode);
1241 1242
out:
	mnt_drop_write(mnt);
Linus Torvalds's avatar
Linus Torvalds committed
1243
}
1244
EXPORT_SYMBOL(touch_atime);
Linus Torvalds's avatar
Linus Torvalds committed
1245 1246

/**
1247 1248
 *	file_update_time	-	update mtime and ctime time
 *	@file: file accessed
Linus Torvalds's avatar
Linus Torvalds committed
1249
 *
1250 1251 1252 1253 1254 1255
 *	Update the mtime and ctime members of an inode and mark the inode
 *	for writeback.  Note that this function is meant exclusively for
 *	usage in the file write path of filesystems, and filesystems may
 *	choose to explicitly ignore update via this function with the
 *	S_NOCTIME inode flag, e.g. for network filesystem where these
 *	timestamps are handled by the server.
Linus Torvalds's avatar
Linus Torvalds committed
1256 1257
 */

1258
void file_update_time(struct file *file)
Linus Torvalds's avatar
Linus Torvalds committed
1259
{
1260
	struct inode *inode = file->f_path.dentry->d_inode;
Linus Torvalds's avatar
Linus Torvalds committed
1261 1262
	struct timespec now;
	int sync_it = 0;
1263
	int err;
Linus Torvalds's avatar
Linus Torvalds committed
1264 1265 1266

	if (IS_NOCMTIME(inode))
		return;
1267 1268 1269

	err = mnt_want_write(file->f_path.mnt);
	if (err)
Linus Torvalds's avatar
Linus Torvalds committed
1270 1271 1272
		return;

	now = current_fs_time(inode->i_sb);
Andreas Mohr's avatar
Andreas Mohr committed
1273 1274
	if (!timespec_equal(&inode->i_mtime, &now)) {
		inode->i_mtime = now;
Linus Torvalds's avatar
Linus Torvalds committed
1275
		sync_it = 1;
Andreas Mohr's avatar
Andreas Mohr committed
1276
	}
Linus Torvalds's avatar
Linus Torvalds committed
1277

Andreas Mohr's avatar
Andreas Mohr committed
1278 1279
	if (!timespec_equal(&inode->i_ctime, &now)) {
		inode->i_ctime = now;
1280
		sync_it = 1;
Andreas Mohr's avatar
Andreas Mohr committed
1281
	}
1282

1283 1284 1285 1286 1287
	if (IS_I_VERSION(inode)) {
		inode_inc_iversion(inode);
		sync_it = 1;
	}

Linus Torvalds's avatar
Linus Torvalds committed
1288 1289
	if (sync_it)
		mark_inode_dirty_sync(inode);
1290
	mnt_drop_write(file->f_path.mnt);
Linus Torvalds's avatar
Linus Torvalds committed
1291 1292
}

1293
EXPORT_SYMBOL(file_update_time);
Linus Torvalds's avatar
Linus Torvalds committed
1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312

int inode_needs_sync(struct inode *inode)
{
	if (IS_SYNC(inode))
		return 1;
	if (S_ISDIR(inode->i_mode) && IS_DIRSYNC(inode))
		return 1;
	return 0;
}

EXPORT_SYMBOL(inode_needs_sync);

int inode_wait(void *word)
{
	schedule();
	return 0;
}

/*
1313 1314 1315 1316 1317 1318 1319 1320 1321
 * If we try to find an inode in the inode hash while it is being
 * deleted, we have to wait until the filesystem completes its
 * deletion before reporting that it isn't found.  This function waits
 * until the deletion _might_ have completed.  Callers are responsible
 * to recheck inode state.
 *
 * It doesn't matter if I_LOCK is not set initially, a call to
 * wake_up_inode() after removing from the hash list will DTRT.
 *
Linus Torvalds's avatar
Linus Torvalds committed
1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335
 * This is called with inode_lock held.
 */
static void __wait_on_freeing_inode(struct inode *inode)
{
	wait_queue_head_t *wq;
	DEFINE_WAIT_BIT(wait, &inode->i_state, __I_LOCK);
	wq = bit_waitqueue(&inode->i_state, __I_LOCK);
	prepare_to_wait(wq, &wait.wait, TASK_UNINTERRUPTIBLE);
	spin_unlock(&inode_lock);
	schedule();
	finish_wait(wq, &wait.wait);
	spin_lock(&inode_lock);
}

1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371
/*
 * We rarely want to lock two inodes that do not have a parent/child
 * relationship (such as directory, child inode) simultaneously. The
 * vast majority of file systems should be able to get along fine
 * without this. Do not use these functions except as a last resort.
 */
void inode_double_lock(struct inode *inode1, struct inode *inode2)
{
	if (inode1 == NULL || inode2 == NULL || inode1 == inode2) {
		if (inode1)
			mutex_lock(&inode1->i_mutex);
		else if (inode2)
			mutex_lock(&inode2->i_mutex);
		return;
	}

	if (inode1 < inode2) {
		mutex_lock_nested(&inode1->i_mutex, I_MUTEX_PARENT);
		mutex_lock_nested(&inode2->i_mutex, I_MUTEX_CHILD);
	} else {
		mutex_lock_nested(&inode2->i_mutex, I_MUTEX_PARENT);
		mutex_lock_nested(&inode1->i_mutex, I_MUTEX_CHILD);
	}
}
EXPORT_SYMBOL(inode_double_lock);

void inode_double_unlock(struct inode *inode1, struct inode *inode2)
{
	if (inode1)
		mutex_unlock(&inode1->i_mutex);

	if (inode2 && inode2 != inode1)
		mutex_unlock(&inode2->i_mutex);
}
EXPORT_SYMBOL(inode_double_unlock);

Linus Torvalds's avatar
Linus Torvalds committed
1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383 1384 1385 1386 1387 1388 1389 1390 1391 1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402 1403 1404 1405 1406 1407 1408
static __initdata unsigned long ihash_entries;
static int __init set_ihash_entries(char *str)
{
	if (!str)
		return 0;
	ihash_entries = simple_strtoul(str, &str, 0);
	return 1;
}
__setup("ihash_entries=", set_ihash_entries);

/*
 * Initialize the waitqueues and inode hash table.
 */
void __init inode_init_early(void)
{
	int loop;

	/* If hashes are distributed across NUMA nodes, defer
	 * hash allocation until vmalloc space is available.
	 */
	if (hashdist)
		return;

	inode_hashtable =
		alloc_large_system_hash("Inode-cache",
					sizeof(struct hlist_head),
					ihash_entries,
					14,
					HASH_EARLY,
					&i_hash_shift,
					&i_hash_mask,
					0);

	for (loop = 0; loop < (1 << i_hash_shift); loop++)
		INIT_HLIST_HEAD(&inode_hashtable[loop]);
}

1409
void __init inode_init(void)
Linus Torvalds's avatar
Linus Torvalds committed
1410 1411 1412 1413
{
	int loop;

	/* inode slab cache */
1414 1415 1416 1417 1418
	inode_cachep = kmem_cache_create("inode_cache",
					 sizeof(struct inode),
					 0,
					 (SLAB_RECLAIM_ACCOUNT|SLAB_PANIC|
					 SLAB_MEM_SPREAD),
1419
					 init_once);
1420
	register_shrinker(&icache_shrinker);
Linus Torvalds's avatar
Linus Torvalds committed
1421 1422 1423 1424 1425 1426 1427 1428 1429 1430 1431 1432 1433 1434 1435 1436 1437 1438 1439 1440 1441 1442 1443 1444 1445 1446 1447 1448 1449 1450 1451 1452 1453 1454 1455 1456 1457

	/* Hash may have been set up in inode_init_early */
	if (!hashdist)
		return;

	inode_hashtable =
		alloc_large_system_hash("Inode-cache",
					sizeof(struct hlist_head),
					ihash_entries,
					14,
					0,
					&i_hash_shift,
					&i_hash_mask,
					0);

	for (loop = 0; loop < (1 << i_hash_shift); loop++)
		INIT_HLIST_HEAD(&inode_hashtable[loop]);
}

void init_special_inode(struct inode *inode, umode_t mode, dev_t rdev)
{
	inode->i_mode = mode;
	if (S_ISCHR(mode)) {
		inode->i_fop = &def_chr_fops;
		inode->i_rdev = rdev;
	} else if (S_ISBLK(mode)) {
		inode->i_fop = &def_blk_fops;
		inode->i_rdev = rdev;
	} else if (S_ISFIFO(mode))
		inode->i_fop = &def_fifo_fops;
	else if (S_ISSOCK(mode))
		inode->i_fop = &bad_sock_fops;
	else
		printk(KERN_DEBUG "init_special_inode: bogus i_mode (%o)\n",
		       mode);
}
EXPORT_SYMBOL(init_special_inode);